Etymology Dictionary

ALTAR,  a place for sacrifices.  (F.,—L.)   Frequently written auter in Mid. Eng., from the O. French auter; so spelt in Wyclif, Acts, xvii. 23, Gen. viii. 20.   Rob. of Brunne, p. 79, has the spelling altere, from the O.F. alter.   And it occurs much earlier, in the Ormulum, l. 1060.   Beyond doubt, the word was borrowed from the French, not the Latin, but the spelling has been altered to make it look more Latin.—O.F. alter, auter (mod. F. autel).—Lat. altare, an altar, a high place.—Lat. altus, high. + Zend. areta, ereta, high (Fick, i. 21).—✔AR, to raise, exalt; cf. Lat. or-iri, to rise up; Fick, i. 19.   See Altitude.

ADDENDA

The word occurs, in the dat. case altare, in the A.S. Gospels, Matt. v. 24; but only in one MS., all the rest (including MS. B., which Kemble has not noted) have wefede, weofede, wigbed, &c.   I therefore adhere to my opinion, that the M.E. alter was borrowed from O. French, and that the spelling altar (with a few exceptions) is comparatively late.   Of course the opposite view, that the word was borrowed (like O. Sax. altari) directly from Latin, is perfectly tenable.   Fortunately, it does not much matter.